Punch and die set



May 1, 1962 Filed Jan. 26, 1960 R. M- BIRKENBEUL ETAL PUNCH AND DIE SET 2 Sheets-Sheet 1 //l l/llmg ROBERT M B/RKENBEUL RONALD R. BLAKLEY INVENTORS A T TORNE Y y 1962 R. M. BIRKENBEUL ETAL 3,032,348

PUNCH AND DIE SET Filed Jan. 26, 1960 2 Sheets-Sheet 2 ROBERT M. B/RKENBEUL RONALD R. B-LAKLEY INVENTORS ATTORNEY United States Patent 3,032,348 PUNCH AND DIE SET Robert M. Birkenbeul and Ronald R. Blakley, Fort Wayne, Ind, assignors to Delta Industries Inc., Fort Wayne, Ind., a corporation of Indiana Filed Jan. 26, 196i), Ser. No. 4,741 16 Claims. (Cl. 279-78) This invention relates to a punch and die $61.. More specifically it relates to holders for both the punch and die which will receive punches and dies having a range of different outside and inside diameters respectively and will support them firmly in accurate coaxial alignment.

It is an object of the invention to provide punch and die holders which will permit the punch and die to be readily removed and inserted.

Another object of the invention is to provide such holders with means for preventing the twisting of the punch and die within their holders.

A furtherobject of the invention is to provide a punch and die set from which the punch may be removed and inserted through the stripper plate, while the die is in the press.

Still another object of the invention is to provide means for retaining the punch and die locking elements in assembled relation in said holders when no punch or die is in place.

It is a further object of the invention to provide holders which will receive shaped punches and corresponding dies and support them in accurate axial and rotational alignment.

Yet another object of the invention is to provide a backing plate for supporting the punch or die and for supporting and guiding the movable parts of the holder.

These and other objects of the invention will become apparent from a study of this specification and the drawings which form a part hereof and in which:

FIGURE 1 is a vertical sectional view of a punch and die mechanism which includes the holders with the punch and die in place therein.

FIGURE 2 is a cross-sectional view taken substantially on the line 2-2 of FIGURE 1 and showing the punch locking rollers.

FIGURE 3 is an elevation of the cage showing the ball and roller receiving recesses.

FIGURE 4 is a cross-sectional view taken substantially I on the line 44 of FIGURE 1 showing the punch centering balls.

FIGURE 5 is a sectional view taken substantially on line 55 of FIGURE 3 showing the collar and roller mounting holes.

FIGURE 6 is a partial elevation of the tool which is I inserted in the holder, showing one of the notches.

FIGURE 7 is an enlarged view showing the relative positions of the parts in their locking positions.

The Punch Holder For convenience, the word tool will hereinafter be used to refer to either the punch, the die or an equivalent tool.

Referring first to FIGURE 1, numeral 1 indicates the punch and stripper supporting block which is provided with a number of holes 3. Each hole is counterbored at 5 to receive the shank and head respectively of a screw 7, on the bottom of which is supported a stripper plate 9. A number of springs 11 are seated in aligned recesses 13 and 15 in the block and stripper plate respectively, and serve to urge the plate away from the block, such motion being limited by the bottoming of the screw heads in the counterbores 5.

A number of holes 17 are formed in the block to receive dowel pins 19 which project into locating holes 23 3,032,348 Patented May 1, 1962 in the body 25 of the punch holder which is indicated generally by numeral 27. Similarly, a number of tapped holes 29 are formed in the block 1 to receive the threaded ends of cap screws 31. The latter pass through corresponding counterbored holes 33 in the holder and hold the holder on the block.

The body 25 is provided with a central hole 35 which is provided with three successively larger cylindrical counterbores 37, 39, and 41. Bore 39 is accurately concentric with the line AA.

A cam ring 43 has a cylindrical exterior which is adapted to fit closely but slidably in bore 39. The upper end of the ring is provided with an inwardly and downwardly converging conical surface 45 which constitutes a cam. This surface terminates in a short cylindrical bore 47 which is counterbored from the bottom at 49 to receive a helical spring 51. The exterior cylindrical portion of the ring, the cam surface, and the bore 47 must be accurately concentric.

A retainer or cage 53 is provided with a central, cylindrical, tool receiving bore 55 which is coaxial with line AA, an external, upper cylindrical surface 57 which fits closely but slidably in bore 47 of the cam ring, an external, lower cylindrical surface 59, which rides in bore 35 and with a radially extending flange 61 which rides in bore 37. The upper surface of this flange serves as a seat for the lower end of the spring 51.

As shown in FIGURES 1 and 3, the upper end of the cage 53 is provided with three, upwardly open, U-shaped notches 63 which are equally spaced about the circumference of the cage. The edges 65 of the notches are chamfered so that the walls thereof converge inwardly and spherical, punch centering bearings 67 are inserted in the notches from the exterior of the cage. These bearings have a diameter which is greater than the narrowest width of the corresponding notches so that they cannot escape through the cage but only project therethrough. The bearings also ride on the cam 45.

The cage is also provided with three circumferentially spaced flats 70 (FIGURES 1 and 3), each of which is provided with a cylindrical, radial hole, 69 (FIGURES 1, 2, 3, and 4). These holes are equally spaced about the circumference of the cage and are preferably vertically aligned with the slots 63 and with the flats 70. The holes are disposed at the same vertical level and are shaved with a rectangular tool to provide, in effect, a right angled track 68, located at each of the four corners of a rectangle, the top and bottom runs of which lie on planes which are perpendicular to the axis AA. A chip 72 is left at the inner end of each track, adjacent the bore 55 to serve as a stop for the cylindrical roller 71 which is inserted in each of the holes. The rollers roll on the tracks, parallel to said planes. The chips prevent the rollers from passing through the cage but permit the rollers to project into the bore 55.

The holder 27 is provided with holes 73, the axes of which lie in a common plane which is perpendicular to the central axis of the cage. This plane is disposed substantially at the same level as the lower walls of the holes 69. The holes intersect the bores 35 and 37 as shown in FIGURES l and 2 and their axes are parallel to the axes of the respective rollers 71. Cylindrical pins or fulcrums 75 are fixed in holes 73 and thus project secantly through the bore 37 at the sides thereof, parallel to flats 70 and below the corresponding rollers 71 as shown in FIGURE 1.

A punch 77 has a cylindrical shank 79 which is provided with three surface notches 81, spaced degrees apart at the general level of the rollers 71. The upper portion of each notch 81 takes the form of an upwardly and outwardly inclined plane 84-having an inclination of 8 degrees from the axis A-A, to form a track which is adapted to have rolling engagement with the corresponding roller.

Since the effectiveness of the locking mechanism depends upon friction between the roller '71 and both the inclined plane 84 and the fulcrum 75, the directions of the forces applied to the parts, when a force is exerted in a withdrawing direction on the tool, will have to be controlled in accordance with the laws of physics pertaining to friction.

The nature of the materials from which the parts are made, the character of the engaging surfaces and the angle of inclination of plane 84 with respect to the plane of the centers of the roller and fulcrum are factors which must be considered.

In actual practice employing hardened tool steel parts having smooth surfaces, we have found that the following relations of the parts provide excellent holding action. V

The plane .84 makes an angle of 8 degrees with the central axis of the tool although this angle may be chosen to suit practical needs. In the lowermost position of the punch, which it occupies in response to a withdrawing force, the plane which includes the line of tangency between the roller 71 and the fulcrum 75 and which is perpendicular to the plane which includes the axes of the roller and fulcrum, makes, with plane 84 an upwardly diverging angle of 7 degrees. This angular relationship may be varied so long as it falls within the angle of repose of the various pairs of frictionally engaged parts of the mechanism. The spring 51 and cage assist in preventing the ejection of the roller from its position between 84 and 75.

The holder will receive any one of a number of punches having diiferent outside diameters. The largest size punch is shown by the solid outline in FIGURES 1 2 and 4 while the minimum diametered punch is shown by the parallel dashed line. A practical limit of the difference in punch diameters which can be used in a holder of one size is inch.

The holder is capable of accepting and properly holding punches of such different diameters concentric with the sleeve because the punches are aligned not by the bore 55 of the cage, but by the balls 67 and rollers 71. All of the balls are moved into the cage the same radial distance by the cam 45 and the rollers are similarly moved the same radial distance by the fulcrum pin 75 as the cage 53 is moved downwardly and the cam ring is moved upwardly by spring 51. The balls engage the cylindrical exterior of the punch shank and the rollers engage the notches which are all of the same depth and form.

A hardened plug 85 is press fitted into counterbore 41 and receives allof the thrust from the punch.

The Die Holder The die holder is constructed along the same general lines as the punch holder. It comprises a die block 87 having a bottom recessed bore 89; a holder 91 having a body 93 provided with an upper bore 95 having counterbores 97, 99 and 101, each of larger diameter than the other; a cam ring 103 having a downwardly facing earn 105; a cage 107 having end slots 109 similar to 63 above and holes 111 similar to 69 above; a spring 113 which is compressed between the cam ring 103 and a flange 115 on the cage; ball bearings 117 in slots 109; rollers 119 in rectangular holes 111; fulcrum pins 121 comparable to pins 75 which are installed in the body 93 in the same manner as pins 75 are installed in body 25 and an annular plug 123 pressed into counterbore 101. This plug, like 85, receives the full thrust of the die.

The die 124 is provided with the usual punch receiving, central bore 125 and its external, cylindrical surface serves as the shank and is provided with notches 127 having downwardly and outwardly inclined planar surface portions for coacting with the rollers 119.

In FIGURE 1, numeral 129 represents the work piece and 131 the slug which has been punched therefrom.

Operation To insert a tool in the holder, it is necessary merely to push the shank thereof into the holder. The leading end of the tool will strike the rollers and displace them and thereby the cage, against the action of the spring. As the rollers are displaced they will roll outwardly on the pins 75 until the tool shank passes. When the leading end of the tool engages the ball bearings, it will force them outwardly and they in turn act on the cam to move the cam ring against the action of the spring. Further movement .of the punch is stopped by the plug. As the notches reach the level of the rollers, the latter will be forced into the notches by the spring and cage which force them to roll about the pins 75 into contact with the corresponding inclined planes 84.

The spring, by means of the cam, also holds the ball hearings in contact with the upper end of the shank. Thus the rollers and balls hold the tool accurately concentric with axis A--A in the holder. No thrust can be imparted to any of the parts of the holder except the plug. The rollers, fulcrums and inclined planes also insure accurate rotational positioning of the tool.

When the punch, for example, is drawn up through the workpiece after a hole is punched, a downward pull is exerted on the punch. However, the relation of the planar surfaces of the punch notches and the centers of the rollers and their respective pins is such as to lock the punch against withdrawal.

To remove the punch from the holder, it is necessary merely to push the cage 53 upwardly with a screwdriver or other tool. The cage depends below the holder body for this reason. This raises the rollers relative to the pins 75 so they may be cammed outwardly by planes of the notches and the punch can be withdrawn through the stripper plate 9 without removing the latter from the press. The punch can also be inserted through the stripper plate.

As noted above, tools of different diameters can be inserted in the same holder, so long as the minimum frees the rollers from the pins and releases the die to be lifted out.

Thus the proper size of die to match the punch can be as readily inserted in the die holder as the punch can be inserted in its holder.

It will be obvious from FIGURE 1 that the holder must be assembled by inserting the rollers in the holes and the cage into the body from the end opposite that which receives the tool. Thereafter, the spring cam ring and ball bearings are inserted in this order. The plug is then pressed into place. Since the balls and rollers cannot pass entirely through the cage, it will be seen that the assembly is held together as a unit by the plug.

It will be seen that the point or cutting end of the punch may be made in any desired form or shape so long as that portion of the shank which enters the holder is cylindrical. Similarly, the opening in the corresponding die will be shaped to accept the punch. The punch and die will be held in their proper rotational positions relative to each other by the proper location of the notches in their shanks.

The fact that the punch and die can be removed and replaced quickly enables production to be maintained without material loss of time for sharpening the tools.

While we havedisclosed a specific embodiment of our invention for purposes of illustration, we do not wish to be strictly limited thereto but desire protection falling fairly within the scope of the appended claims.

We claim:

1. A tool and tool holder, said holder comprising a body defining a guide bore having a central axis, a generally tubular cage, means for mounting said cage for coaxial reciprocation in said bore, said cage having a coaxial bore for receiving a tool having a cylindrical shank, means in said cage and body for receiving and centering one end of said shank coaxially in said cage, said cage defining a number of circumferential, equally spaced, radially extending roller guide means, a roller mounted in each guide means, for movement toward and from said tool shank, said tool shank defining a like number of circumferential, equally spaced notches, one for each roller, each notch being defined in part by an inclined plane diverging away from the point of the punch, said rollers projecting through said cage for engagement with said planes, a like number of fulcrum means, one adjacent each roller, mounted on said body and extending through said guide bore thereof parallel to its roller, means for yieldably urging said cage and rollers toward said fulcrum means, to cause said fulcrum means to project said rollers into contact with the planes of the notches.

2. The structure defined by claim 1, wherein said fulcrum means intersect the guide bore of the body.

3. The structure defined by claim 2 wherein said fulcrum means comprise cylinders disposed as secants of said body guide bore.

4. The structure defined by claim 1 wherein the angle between the inclined plane of each notch and a plane which is tangent to the corresponding roller and fulcrum at the line of their mutual contact, is less than the angle of repose.

5. The structure defined by claim 4 wherein said angle is substantially 7 degrees.

6. The structure defined by claim 1 wherein said cage projects beyond the end of said body.

7. The structure defined by claim 1 wherein said roller guide means each comprise a radial hole of generally rectangular cross-section defined by said cage and intersecting said coaxial bore, and stop means disposed adjacent the inner end of the hole to prevent passage of the associated roller into said coaxial bore.

8. A tool and holder, said holder comprising a body defining a guide bore, a cam ring slidable in one end of said bore and having a conical cam surface diverging outwardly toward the adjacent end of said guide bore, said ring having a central bore, a generally tubular cage slidably mounted in said central bore and having a bore, a tool having a cylindrical shank, received in said cage bore, said cage defining a number of circumferentially equally spaced, axially extending slots disposed adjacent said cam surface, a ball bearing disposed in each notch, and adapted to project therethrough into said cage bore, yieldable means for urging said cam ring toward said balls to project them into said cage bore to center the end of the tool shank with respect to said bore and additional means supported by said cage and body, and movable into engagement with the other end of said shank by said yieldable means, for centering said other end coaxially in said cage and for releasably holding said shank against withdrawal from said cage.

9. The structure defined by claim 8 wherein said releasable holding means includes wedgi-ng means for preventing withdrawal of said tool shank axially from said cam ring.

10. The structure defined by claim 8 wherein said notches comprise axially extending slots, each slot having walls converging toward said central axis to permit the associated ball to extend through but to prevent passage of the associated ball through the slot.

11. A tool and tool holder, said holder comprising a body having a guide bore, a cam ring slidable in one end of said bore and having a conical cam surface diverging outwardly toward the adjacent end of said bore, said ring having a central bore, a generally tubular cage slidable in said central bore, a tool having a cylindrical shank adapted to enter said cage bore and provided with circumferential, equally spaced notches at a predetermined level, each notch being defined in part by an inclined plane diverging away from the point of the punch, said cage having a like number of circumferential, equally spaced axial slots disposed adjacent said cam, a ball bearing mounted in each of said slots and projecting therethrough into the path of said shank, said cage defining a like number of circumferential equally spaced, radially extending roller guide passages terminating adjacent said planes, a roller disposed in each passage with its axis disposed normal to the axis of the cage, a like number of fulcrum means fixed on said body, extending as secants through said guide bore, adjacent and parallel to each of said rollers, yieldable means for urging said cam ring toward said ball bearings and said cage and rollers toward said fulcrum means, whereby said ball bearings are projected by said cam ring into centering engagement with said tool shank and said rollers are projected into centering and locking engagement with the planes of said tool shank.

12. The structure defined by claim 11 wherein said slots are defined by inwardly converging walls to permit said ball bearings to project into but prevent passage thereof into the cage bore.

13. The structure defined by claim 11 wherein the angle between the plane of each notch and a plane which is tangent to the corresponding roller and fulcrum at the line of their mutual contact, is less than the angle of repose.

14. The structure defined by claim 13 wherein said angle is substantially 7 degrees.

=15. The structure defined by claim 11 which includes a plug fastened in the end of said body adjacent said cam ring to serve as a stop for the end of said tool shank and said ball bearings.

16. The structure defined by claim 11 wherein said cage defines an outwardly extending flange disposed above said fulcrum means and coacting therewith to prevent movement of said cage past said fulcrum means and a plug fastened in the end of said body adjacent said cam ring.

References Cited in the file of this patent UNITED STATES PATENTS 

